Goto Account Tab | Scroll down and click on "Transfer Accounts" link on bottom right side.

also read following helpful document.

User Permissions Needed

To mass transfer accounts, service contracts, or custom objects:

“Transfer Record”

AND

“Edit” on the object type

To mass transfer leads:

“Transfer Leads” OR “Transfer Record”

AND

“Edit” on leads

Use the Mass Transfer tool to transfer multiple accounts, leads, service contracts, and custom objects from one user to another.Note

To transfer any records that you do not own, you must have the required user permissions as well as read sharing access on the records.

Choose Your Name | Setup | Data Management | Mass Transfer Records.

Click the link for the type of record to transfer.

Optionally, fill in the name of the existing record owner in the Transfer from field. For leads, you can transfer from users or queues.

In the Transfer to field, fill in the name of new record owner. For leads, you can transfer to users or queues.

If your organization uses divisions, select the Change division.... checkbox to set the division of all transferred records to the new owner’s default division.

When transferring accounts, you can:

Select the Transfer open opportunities not owned by the existing account owner checkbox if you want to transfer open opportunities owned by other users that are associated with the account.

Select the Transfer closed opportunities checkbox if you want to transfer closed opportunities associated with the account. This option applies only to closed opportunities owned by the account owner; closed opportunities owned by other users are not changed.

Select the Transfer open cases owned by the existing account owner checkbox if you want to transfer open cases that are owned by the existing account owner and associated with the account.

Select the Transfer closed cases checkbox if you want to transfer closed cases that are owned by the existing account owner and associated with the account.

Select the Keep Account Team checkbox if you want to maintain the existing account team associated with the account. Deselect this checkbox if you want to remove the existing account team associated with the account.

Select the Keep Sales Team on all opportunities... checkbox if you want to maintain the existing sales team on any opportunities associated with this account.Note

If you transfer closed opportunities, the sales team is maintained, regardless of this setting.

Enter search criteria that the records you are transferring must match. For example, you could search accounts in California by specifying Billing State/Province equals CA.

Click Find.

Select the checkbox next to the records you want to transfer. Optionally, check the box in the column header to select all currently displayed items.Note

If duplicate records are found, you must select only one of the records to transfer. Transferring duplicate records results in an error.

Duplicate records may display if you filter leads based on Campaign Member Status and a matching lead has the same campaign member status on multiple campaigns. For example, if you specify Campaign Member Status equals Sent, and a matching lead named John Smith has the status Sent on two campaigns, his record will display twice.

Click Transfer.

Transfer of Associated Items

When you change record ownership, some associated items that are owned by the current record owner are also transferred to the new owner.

Record

Associated items that are also transferred

Accounts

Contacts (on business accounts only), attachments, notes, open activities, open opportunities owned by the current account owner, and optionally, closed opportunities and open opportunities owned by other users.

Leads

Open activities. When transferring leads to a queue, open activities are not transferred.

Access to Transferred Items

When transferring accounts and their related data in Professional, Enterprise, Unlimited, and Developer Editions, all previous access granted by manual sharing, Apex managed sharing, or sharing rules is removed. New sharing rules are then applied to the data based on the new owner. The new owner may need to manually share the transferred accounts and opportunities as necessary to grant access to certain users.

All Answers

Goto Account Tab | Scroll down and click on "Transfer Accounts" link on bottom right side.

also read following helpful document.

User Permissions Needed

To mass transfer accounts, service contracts, or custom objects:

“Transfer Record”

AND

“Edit” on the object type

To mass transfer leads:

“Transfer Leads” OR “Transfer Record”

AND

“Edit” on leads

Use the Mass Transfer tool to transfer multiple accounts, leads, service contracts, and custom objects from one user to another.Note

To transfer any records that you do not own, you must have the required user permissions as well as read sharing access on the records.

Choose Your Name | Setup | Data Management | Mass Transfer Records.

Click the link for the type of record to transfer.

Optionally, fill in the name of the existing record owner in the Transfer from field. For leads, you can transfer from users or queues.

In the Transfer to field, fill in the name of new record owner. For leads, you can transfer to users or queues.

If your organization uses divisions, select the Change division.... checkbox to set the division of all transferred records to the new owner’s default division.

When transferring accounts, you can:

Select the Transfer open opportunities not owned by the existing account owner checkbox if you want to transfer open opportunities owned by other users that are associated with the account.

Select the Transfer closed opportunities checkbox if you want to transfer closed opportunities associated with the account. This option applies only to closed opportunities owned by the account owner; closed opportunities owned by other users are not changed.

Select the Transfer open cases owned by the existing account owner checkbox if you want to transfer open cases that are owned by the existing account owner and associated with the account.

Select the Transfer closed cases checkbox if you want to transfer closed cases that are owned by the existing account owner and associated with the account.

Select the Keep Account Team checkbox if you want to maintain the existing account team associated with the account. Deselect this checkbox if you want to remove the existing account team associated with the account.

Select the Keep Sales Team on all opportunities... checkbox if you want to maintain the existing sales team on any opportunities associated with this account.Note

If you transfer closed opportunities, the sales team is maintained, regardless of this setting.

Enter search criteria that the records you are transferring must match. For example, you could search accounts in California by specifying Billing State/Province equals CA.

Click Find.

Select the checkbox next to the records you want to transfer. Optionally, check the box in the column header to select all currently displayed items.Note

If duplicate records are found, you must select only one of the records to transfer. Transferring duplicate records results in an error.

Duplicate records may display if you filter leads based on Campaign Member Status and a matching lead has the same campaign member status on multiple campaigns. For example, if you specify Campaign Member Status equals Sent, and a matching lead named John Smith has the status Sent on two campaigns, his record will display twice.

Click Transfer.

Transfer of Associated Items

When you change record ownership, some associated items that are owned by the current record owner are also transferred to the new owner.

Record

Associated items that are also transferred

Accounts

Contacts (on business accounts only), attachments, notes, open activities, open opportunities owned by the current account owner, and optionally, closed opportunities and open opportunities owned by other users.

Leads

Open activities. When transferring leads to a queue, open activities are not transferred.

Access to Transferred Items

When transferring accounts and their related data in Professional, Enterprise, Unlimited, and Developer Editions, all previous access granted by manual sharing, Apex managed sharing, or sharing rules is removed. New sharing rules are then applied to the data based on the new owner. The new owner may need to manually share the transferred accounts and opportunities as necessary to grant access to certain users.

On the Accounts tab, if you have permissions, you can use the "Transfer Accounts" Tool. Note that if the existing Account Owner is the same owner as Contacts or open Opportunities, their owners will be changed as well.